In this week's edition of Extra Time, we have the thrills and spills of the BMX World Champs in Auckland. We hear from New Zealand Olympics silver medallist Sarah Walker and the Australian men's BMX world champion Sam Willoughby. We preview the Super rugby semi-final between the Chiefs and the Crusaders. The Chiefs are the defending champions, the New Zealand Conference winners and have hometown advantage so why are the Crusaders the favourites? And Mahe Drysdale's back on the water and straight into the New Zealand team for the rowing world champs in South Korea.